Synthesis of Selenium-Decorated N-Oxide Isoquinolines: Arylseleninic Acids in Selenocyclization Reactions

Herein, we describe the use of benzeneseleninic acid derivatives (BSA) as a bench-stable and easy to handle selenium reagent to access 4-(selanyl)isoquinoline-N-oxides through the selenocyclization of o-alkynyl benzaldehyde oximes. The reaction is conducted in refluxing methanol, allowing the thermal generation of electrophilic selenium species in situ. By this new protocol, a library of 19 selenium-decorated N-oxide isoquinolines was accessed in up to 96% yield with an outstanding substrate tolerance and the feasibility to scale it up 10 times (from 0.25 to 2.5 mmol).

Selenylated Analogs of Tacrine: Synthesis, In Silico and In Vitro Studies of Toxicology and Antioxidant Properties

We present our results on the synthesis and preliminary in silico and in vitro studies of the toxicology and antioxidant properties of selenylated analogs of Tacrine. Initially, we synthesized 2-aminobenzonitriles containing an organic selenium moiety, resulting in sixteen compounds with various substituents linked to the portion derived from diorganyl diselenide. These compounds were then used as substrates in reactions with cyclic ketones, in the presence of 1.4 equivalents of trifluoroboroetherate as a Lewis acid, to synthesize selenylated analogs of Tacrine with yields ranging from 20 % to 87 %. In silico studies explored computational parameters related to antioxidant activity and hepatotoxicity. In vitro studies elucidated the antioxidant effects of Tacrine and its selenium hybrid (TSe) in neutralizing ABTS radicals, scavenging DPPH radicals, and reducing iron ions. Additionally, the acute oral toxicity of one synthesized compound was evaluated.

Rhodium-Catalyzed Isoquinoline Synthesis Using Vinyl Selenone as Oxidizing Acetylene Surrogate

Isoquinoline is a privileged structure in many bioactive compounds and valuable ligands. Transition-metal-catalyzed oxidative annulation of imine derivatives has become a promising synthetic method; however, catalytic synthesis of 3,4-nonsubstituted isoquinolines by formal acetylene annulation has been scarce to date. Herein, we introduce vinyl selenone as an effective acetylene surrogate for the Rh-catalyzed annulative coupling under mild conditions. The Se fragment can be recovered as diselenide and recycled. The product can readily be converted to 1-aminoisoquinolines.

Meyer-Schuster-Type Rearrangement of Propargylic Alcohols into α-Selenoenals and -enones with Diselenides

We describe a mild and broadly applicable protocol for the preparation of a diverse array of multisubstituted α-selenoenals and -enones from readily accessible propargylic alcohols and diselenides. The transformation proceeds via the Selectfluor-promoted selenirenium pathway, which enables selenenylation/rearrangement of a variety of propargylic alcohols. Gram-scale experiments showed the potential of this synergistic protocol for practical application.